I think the YouTube video essay format just isn't for me, but a lot of the content seems poorly edited and he beings to endlessly ramble by the middle. I haven't seen anyone serious suggest that if it wasn't for the MCU people would be watching art films. The video starts off with a bunch of these "people are saying" claims, but by the numbers aren't these films wildly commercially successful, review well, audience scores are always high, people love these characters and include them in multiple aspects of their lives (costume sales probably back this up), etc. All that suggests that the MCU is getting the recognition he believes it deserves.
It was essentially Passion of the Christ in the theater I was at weeks after release for the "I don't want to go" scene (myself included.) There's going to be a lot of contrarians and people who these films don't appeal to but creating a false narrative like this seems harmful. A group that allows this persecuted majority idea to flow freely seems perfect for more harmful ideas. I guess look at the hate Brie Larson gets for being "anti man" to back that up.
Going back to the video essay format, him ending the video on that overly sentimental "these are my heroes 🥺", makes it harder to critique the video and just adds to why I don't like the format.